[pve-devel] [PATCH access-control 1/3] authenticate_2nd_new: only lock tfa config for recovery keys

[Dominik Csapak]

we currently only need to lock the tfa config when we got a recovery key
as a tfa challenge response, since that's the only thing that can
actually change the tfa config (every other method only reads from
there).

so to do that, factor out the code that was inside the lock, and call it
with/without lock depending on the tfa challenge response

Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
---
 src/PVE/AccessControl.pm | 127 +++++++++++++++++++++------------------
 1 file changed, 69 insertions(+), 58 deletions(-)

diff --git a/src/PVE/AccessControl.pm b/src/PVE/AccessControl.pm
index c32dcc3..c45188c 100644
--- a/src/PVE/AccessControl.pm
+++ b/src/PVE/AccessControl.pm
@@ -786,79 +786,90 @@ sub authenticate_2nd_old : prototype($$$) {
     return wantarray ? ($username, $tfa_data) : $username;
 }
 
-# Returns a tfa challenge or undef.
-sub authenticate_2nd_new : prototype($$$$) {
+sub authenticate_2nd_new_do : prototype($$$$) {
     my ($username, $realm, $otp, $tfa_challenge) = @_;
+    my ($tfa_cfg, $realm_tfa) = user_get_tfa($username, $realm, 1);
 
-    my $result = lock_tfa_config(sub {
-	my ($tfa_cfg, $realm_tfa) = user_get_tfa($username, $realm, 1);
-
-	if (!defined($tfa_cfg)) {
-	    return undef;
-	}
-
-	my $realm_type = $realm_tfa && $realm_tfa->{type};
-	# verify realm type unless using recovery keys:
-	if (defined($realm_type)) {
-	    $realm_type = 'totp' if $realm_type eq 'oath'; # we used to call it that
-	    if ($realm_type eq 'yubico') {
-		# Yubico auth will not be supported in rust for now...
-		if (!defined($tfa_challenge)) {
-		    my $challenge = { yubico => JSON::true };
-		    # Even with yubico auth we do allow recovery keys to be used:
-		    if (my $recovery = $tfa_cfg->recovery_state($username)) {
-			$challenge->{recovery} = $recovery;
-		    }
-		    return to_json($challenge);
-		}
+    if (!defined($tfa_cfg)) {
+	return undef;
+    }
 
-		if ($otp =~ /^yubico:(.*)$/) {
-		    $otp = $1;
-		    # Defer to after unlocking the TFA config:
-		    return sub {
-			authenticate_yubico_new(
-			    $tfa_cfg, $username, $realm_tfa, $tfa_challenge, $otp,
-			);
-		    };
+    my $realm_type = $realm_tfa && $realm_tfa->{type};
+    # verify realm type unless using recovery keys:
+    if (defined($realm_type)) {
+	$realm_type = 'totp' if $realm_type eq 'oath'; # we used to call it that
+	if ($realm_type eq 'yubico') {
+	    # Yubico auth will not be supported in rust for now...
+	    if (!defined($tfa_challenge)) {
+		my $challenge = { yubico => JSON::true };
+		# Even with yubico auth we do allow recovery keys to be used:
+		if (my $recovery = $tfa_cfg->recovery_state($username)) {
+		    $challenge->{recovery} = $recovery;
 		}
+		return to_json($challenge);
 	    }
 
-	    my $response_type;
-	    if (defined($otp)) {
-		if ($otp !~ /^([^:]+):/) {
-		    die "bad otp response\n";
-		}
-		$response_type = $1;
+	    if ($otp =~ /^yubico:(.*)$/) {
+		$otp = $1;
+		# Defer to after unlocking the TFA config:
+		return sub {
+		    authenticate_yubico_new(
+			$tfa_cfg, $username, $realm_tfa, $tfa_challenge, $otp,
+		    );
+		};
 	    }
+	}
 
-	    die "realm requires $realm_type authentication\n"
-		if $response_type && $response_type ne 'recovery' && $response_type ne $realm_type;
+	my $response_type;
+	if (defined($otp)) {
+	    if ($otp !~ /^([^:]+):/) {
+		die "bad otp response\n";
+	    }
+	    $response_type = $1;
 	}
 
-	configure_u2f_and_wa($tfa_cfg);
+	die "realm requires $realm_type authentication\n"
+	    if $response_type && $response_type ne 'recovery' && $response_type ne $realm_type;
+    }
 
-	my $must_save = 0;
-	if (defined($tfa_challenge)) {
-	    $tfa_challenge = verify_ticket($tfa_challenge, 0, $username);
-	    $must_save = $tfa_cfg->authentication_verify($username, $tfa_challenge, $otp);
-	    $tfa_challenge = undef;
-	} else {
-	    $tfa_challenge = $tfa_cfg->authentication_challenge($username);
-	    if (defined($otp)) {
-		if (defined($tfa_challenge)) {
-		    $must_save = $tfa_cfg->authentication_verify($username, $tfa_challenge, $otp);
-		} else {
-		    die "no such challenge\n";
-		}
+    configure_u2f_and_wa($tfa_cfg);
+
+    my $must_save = 0;
+    if (defined($tfa_challenge)) {
+	$tfa_challenge = verify_ticket($tfa_challenge, 0, $username);
+	$must_save = $tfa_cfg->authentication_verify($username, $tfa_challenge, $otp);
+	$tfa_challenge = undef;
+    } else {
+	$tfa_challenge = $tfa_cfg->authentication_challenge($username);
+	if (defined($otp)) {
+	    if (defined($tfa_challenge)) {
+		$must_save = $tfa_cfg->authentication_verify($username, $tfa_challenge, $otp);
+	    } else {
+		die "no such challenge\n";
 	    }
 	}
+    }
 
-	if ($must_save) {
-	    cfs_write_file('priv/tfa.cfg', $tfa_cfg);
-	}
+    if ($must_save) {
+	cfs_write_file('priv/tfa.cfg', $tfa_cfg);
+    }
 
-	return $tfa_challenge;
-    });
+    return $tfa_challenge;
+}
+
+# Returns a tfa challenge or undef.
+sub authenticate_2nd_new : prototype($$$$) {
+    my ($username, $realm, $otp, $tfa_challenge) = @_;
+
+    my $result;
+
+    if (defined($otp) && $otp =~ m/^recovery:$/) {
+	$result = lock_tfa_config(sub {
+	    authenticate_2nd_new_do($username, $realm, $otp, $tfa_challenge);
+	});
+    } else {
+	$result = authenticate_2nd_new_do($username, $realm, $otp, $tfa_challenge);
+    }
 
     # Yubico auth returns the authentication sub:
     if (ref($result) eq 'CODE') {
-- 
2.30.2